National registry diagnoses agree with medical records on hospitalized asthmatic children

Aim: The present study was performed to explore the validity of discharge diagnoses on asthma in the Danish National Patient Registry compared with medical records. Methods: A review of medical records on all acute hospital admissions of 6-14-year-old children in 10 Danish hospitals between July and December 2002 was conducted. The personal registration number and dates on admissions due to asthma were sent to the Danish National Patient Registry for information on discharge diagnoses, and admission and discharge dates. Agreement between medical records and the Danish National Patient Registry was sought by sensitivity, specificity, and the positive and negative predictive value. Results: Medical records of 3550 children aged 6-14 years were reviewed. A total of 300 admissions were due to asthma, 271 of which were also registered with an asthma diagnosis unit in the Danish National Patient Registry. Collection of data in the Danish National Patient Registry showed a surplus of 49 admissions due to asthma compared to hospital record data. The sensitivity of an asthma diagnosis in the registry then was 0.90, specificity 0.99, positive predictive value 0.85 and negative predictive value 0.99. Conclusions: Data on paediatric asthma diagnoses in the Danish National Patient Registry are valid and may serve as useful tools in research.